ROSE FAMILY 175 



and Ivesia (Proc. Am. Acad. 8:549-573, — 1873). Greene, E. L., West American phases of the 

 genus Potontilla (Pitt. 1:95-106,-1887) ; The genus Tridophyllum (Lflts. 1:188-189,-1906); 

 Certain rosaceous genera (Lflts. 1:237-238, — 1906); Four new Potentillaceae (Lflts. 2:137- 

 139,-1911). Eydberg, P. A., Notes on Potentilla (Bull. Torr. Club 23:244-248, 259-265, 301- 

 306, 394-399, 429-435,-1896; 24:1-13,-1897) ; Some changes in the nomenclature of N. Am. 

 Eosaceae (Bull. Torr. Club 25:54-56,-1898) ; A monograph of the N. Am. Potentilleae (Mem. 

 Dept. Bot. Columbia Univ. 2:1-223,-1898); Further studies on the Potentilleae (Bull. Torr. 

 Club 28:173-183,-1901); Potentilleae (N. Am. Fl. 22:268-377,-1908); Notes on Eosaceae: 

 Horkelia, Horkeliella, Ivesia, Purpusia, Comarella, Stellariopsis (Bull. Torr. Club 36:404-407, — 

 1909); Potentilla (I.e. 37:375-386, 487-502,-1910; 38:79-89,-1911); Argentina, Comarum, 

 Duchesnea, Fragaria, Sibbaldia, Sibbaldiopsis, Dasiphora, Drymocallis, Chamaerhodos (I.e. 38: 

 351-367,-1911). Wolf, Th., Monographie der Gatt. Potentilla (Biblio. Bot. 16^:1-714, 1. 1-20,— 

 1908). Fernald, M. L., The representatives of Potentilla anserina in eastern N. Am. (Ehod. 

 11 :l-9, — 1909) ; The American variations of Potentilla palustris (Ehod. 16 :5-ll, pi. 106, — 1914). 

 Munz, P. A., and Johnston, I. M., PotentUlas of S. Cal. (Bull. S. Cal. Acad. 24:5-25,-1925). 



A. Ovules ascending; styles sub-basal; filaments filiform; achenes hairy 

 or glabrous; perennials. 



Stamens about 20 to 25 ; leaves pinnate. 



Low shrub ; petals yellow ; styles obconic, short ; achenes hairy. — Subgenus Dasiphora 



1. P. fruticosa. 

 Perennial herbs ; achenes glabrous. 



Petals dark purple; stems ascending, rooting below; styles filiform, subequal to mature 



achenes. — Subgenus Comarum 2. P. palustris. 



Petals yellow; stems wholly creeping, rooting at joints; leaves white-silky beneath; 



styles short. — Subgenus Argentina 3. P. anserina. 



Stamens 5; petals j^ellow, minute; leaves 3-foliolate; styles obconic, short; achenes 10 to 15. — 

 Subgenus Sibbaldia 4. P. sibbaldii. 



B. Ovules pendulous; styles subterminal (except in P. glandulosa) ; 

 achenes glabrous; herbs. 



L Stamens 15 to 25 (10 in nos. 7, 8, and 10), inserted on a disk or annular thickening near 



THE receptacle; FILAMENTS FILIFORM; PETALS YELLOW (SOMETIMES WHITISH OE 



cream-color); CALYX-TUBE SAUCER-SHAPED; ACHENES (USUALLY) MANY; 



PERENNIAL OR ANNUAL HERBS. — Subgenus EUPOTENTILLA. 



1. Leaves ternate or pinnate; leaflets usually S to 5 (7 to 11), merely toothed, not dissected; in- 



florescence more or less leafy; herbage often glandular; petals yelloio 



(rarely whitish or cream-color ) . 



Styles sub-basal, spindle-shaped, not longer than the mature achenes (except in var. cuneifolia) ; 



herbage more or less glandular-pubescent; perennial 5. P. glandulosa. 



Styles subterminal, conoid to filiform-subulate. 



Stamens 25 to 30; styles filiform-subulate, about equaling mature achenes; perennial 



6. P. saxosa. 

 Stamens 10 to 20 ; styles very short-conoid ; achenes numerous; inflorescence leafy, branching, 

 often more or less sympodial ; annuals or biennials. 

 Leaflets 5; stems erect or ascending; cyme spreading; annual; stamens 10....7. P. rivalis. 

 Leaflets 3 ; cyme often falsely racemose. 



Stems prostrate to erect; leaflets cuneate-obovate, incised-serrate ; stamens 10; 



annual 8. P. leucocarpa. 



Stems erect; leaflets broadly to narrowly obovate, coarsely crenate or dentate; 



annuals or biennials. 



Stamens 15 to 20 ; achenes tan or brownish, rugulose ; leaves obovate or obovate- 



oblong, incised-dentate ; flowers 5 to 6 lines broad.-9. P. monspeliensis. 



Stamens about 10; achenes whitish, smooth; leaves broadly obovate, coarsely 



crenate ; flowers 3 lines broad 10. P. biennis. 



2. Leaves pinnate or palmate; leaflets (S or) 5 to many, toothed or (usually) deeply incised or cleft 



into lanceolate or linear-oblong lobes; inflorescence bracteate ; petals yellow ; per- 

 ennial herbs, the stems from a simple or branched short root-crown. 

 a. Styles thickish, not longer than mature achenes; leaflets deeply pinnately incised; 

 herbage tomentose, not glandular; White Mts. 

 Leaves pianate; leaflets (5 or) 9 to 11, oblong ia outline, greenish above, tomentose below, the 



segments with revolute margins 11. P. pennsylvanica. 



Leaves mostly palmate; leaflets usually 5, obovate in outline, often sUvery-silky on both sides; 

 segments without revolute margins 12. P. pseudosericea. 



